This invention relates to a method for connecting pipes, hoses, tubes or the like to a fluid port, such as a tap or another pipe, and a pipe connecting piece. The method will generally be most useful for joining plastics pipes, however it can be utilised to join metal pipes as well.
In the past, various devices have been used for connecting pipes end to end. However, such devices have tended to be bulky and expensive because of the need to ensure that once the fitting is connected to the pipes, there will be no leak of fluid from within the pipes through the joint.
A common device for joining pipes utilises a metal fitting with a threaded central portion and an end portion of such a diameter that when it is inserted into the end of a pipe it causes the pipe end to expand. A metal collar is then screwed to the central portion to clamp the pipe against the end portion. These devices are cumbersome.
Alternative means for clamping the pipe to the end portion are also utilised. A metal sleeve may be placed over the pipe above the inserted end portion and crimped or swaged in place. This results in a joint that is prone to leakage due to the `creep` of standard pipes and may have a weak point at the connection between the end portion and the central portion of the fitting. Crimping the sleeve generally results in the formation of an `ear` or loop of material from the sleeve which reduces the remainder of the sleeve in size. This weakens the sleeve, and deforms the pipe, often creating a minute channel between the pipe and the end portion that allows leakage of fluid carried by the pipe, particularly when it is a gas. If the sleeve is to be crimped again it is necessary to position the crimping device at exactly the same position as previously. Crimping may also deform and damage the end portion of the fitting.